(DCP029) CHANGES IN THE INCIDENCE OF GESTATIONAL DIABETES IN ALBERTA DURING THE COVID-19 PANDEMIC: A POPULATION-BASED STUDY

Background: Gestational diabetes is common and associated with adverse pregnancy outcomes. With changes to prenatal care and screening during the COVID-19 pandemic, significant changes were made to care delivery in individuals with gestational diabetes; however, it is unknown if these healthcare changes and government restrictions affected the incidence of gestational diabetes. This study’s aim was to describe the incidence of gestational diabetes through the waves of the COVID-19 pandemic in Alberta.

METHODS AND RESULTS:
This is a population-based, retrospective cohort study using health administrative data. All births >20 weeks’ gestation from 1Jan2017-31Dec2021 were identified. Multiple gestations, and births outside of the hospital were excluded. Births were linked to the Discharge Abstract Database, National Ambulatory Care Reporting System, Practitioner Claims Database, and the Pharmaceutical Information Network using the mother's personal health number. We used the Government Response Stringency Index to quantify the severity of public health restrictions. An interrupted time series analysis was used to examine point prevalence trends of the incidence of gestational diabetes prior to the pandemic and for each pandemic wave period. Since gestational diabetes is a condition of late pregnancy, the incidence of gestational diabetes per total deliveries ≥28 weeks pregnancy was described.

Prior to the COVID-19 pandemic (baseline), the incidence of gestational diabetes was rising in Alberta (p < 0.0001). The interrupted time series analyses are summarized in Figure 1. During Wave 1, where there were severe government restrictions but few COVID-19 cases, there were significant decreases in the incidence and the change in incidence proportions over time for gestational diabetes diagnosis (level change p=0.001; slope change p=0.049). During Wave 3, there was again a decrease in both the incidence and the change in incidence proportions over time of diagnosed gestational diabetes (level change p=0.025; slope change p< 0.0001). However, in Wave 4, where there were limited government restrictions but high case counts, there was an increase in the change in incidence of gestational diabetes proportions over time.

Conclusion: There were significant changes in the incidence of diagnosed gestational diabetes over the first four waves of the COVID-19 pandemic in Alberta which corresponded to COVID-19 case counts and COVID-19 related restrictions. In the fourth wave of the pandemic, despite high COVID-19 case counts, gestational diabetes incidence continued to rise. We postulate that the changes in gestational diabetes incidence reflect changes in access to testing, practitioner or patient comfort, and diagnostic criteria rather than changes in the underlying pathophysiology.